Abstract Introduction To evaluate rotational fibrin‐based thromboelastometry (ROTEM ® FIBTEM) with amplitude of clot firmness at 5 min (A5) as an early point‐of‐care parameter for predicting progression to severe postpartum hemorrhage, and compare its predictive value with that of fibrinogen. Material and methods Prospective cohort study in the Netherlands including women with 800–1500 ml of blood loss within 24 h following birth. Blood loss was quantitatively measured by weighing blood‐soaked items and using a fluid collector bag in the operating room. Both FIBTEM A5 values and fibrinogen concentrations (Clauss method) were measured between 800 and 1500 ml of blood loss. Predictive accuracy of both biomarkers for the progression to severe postpartum hemorrhage was measured by area under the receiver operating curves (AUC). Severe postpartum hemorrhage was defined as a composite endpoint of (1) total blood loss >2000 ml, (2) transfusion of ≥4 packed cells, and/or (3) need for an invasive intervention to cease bleeding. Results Of the 391 women included, 72 (18%) developed severe postpartum hemorrhage. Median (IQR) volume of blood loss at blood sampling was 1100 ml (1000–1300) with a median (interquartile range [IQR]) fibrinogen concentration of 3.9 g/L (3.4–4.6) and FIBTEM A5 value of 17 mm (13–20). The AUC for progression to severe postpartum hemorrhage was 0.53 (95% confidence interval [CI] 0.46–0.61) for FIBTEM A5 and 0.58 (95% CI 0.50–0.65) for fibrinogen. Positive predictive values for progression to severe postpartum hemorrhage for FIBTEM A5 ≤12 mm was 22.5% (95% CI 14–33) and 50% (95% CI 25–75) for fibrinogen ≤2 g/L. Conclusions The predictive value of FIBTEM A5 compared to fibrinogen concentrations measured between 800 and 1500 ml of blood loss following childbirth was poor to discriminate between women with and without progression towards severe postpartum hemorrhage.